Pulled common keyserver label out of `CommunityCreationModal` and `CommunityCreationMembersModal`.
> Why not make it more general and put it in `components`
It has a hardcoded keyserver name (ashoat) so I think it makes sense to keep its use as limited as possible. `CommunityCreationKeyserverLabel` could be the basis for a more general purpose `KeyserverLabel` component in the future.